1. Field of the Invention
The invention relates to a system and method for encrypting content sent to a user. Content includes any electronic file or application, including video, audio, datacast, video games, and other computer programs. More specifically, the invention relates to software for encrypting packets received at a user terminal and restricting decryption of the packets to the user terminal where the packets were received and encrypted.
2. Description of the Background
Media content is sent to users in a variety of methods. For example, terrestrial television signals are broadcast through the airwaves using a radio frequency signal, which is received by a user with a receiver connected to a television display. A terrestrial television receiver includes an antenna for receiving the signal, which must be placed in a position where it can receive the signals. Television reception from a radio frequency signal is often poor if the user is located far from the signal broadcast or if the user has difficulty placing the antenna in the correct position to receive the signal. Radio frequency signals received by a television set are also sent to all television receivers in a geographic area, and therefore it is not possible to control which users have access to specific media content. It is also difficult to monitor what content users are viewing.
Cable broadcasts employ a path to a user terminal without many of the interferences of terrestrial television. Satellite offers a digital representation of a signal with more of a line-of-sight path to the user terminal. As used herein, a “user terminal” is an electronic device for receiving media content such as a television, personal computer (“PC”) or set top box. Cable and satellite broadcasters are also able control which users have access to specific content. Cable and satellite broadcast signals may be encrypted, or “scrambled,” such that only users with a de-encryption code or “key” may view the content.
By controlling which users are allowed to view content, cable and satellite broadcasters are able to charge users based on the content that the viewer wishes to receive. For example, cable and satellite providers often charge a set periodic fee, normally a monthly fee, for a content package. Each content package contains a specified number of channels to which the user is given access for a set fee. In addition, cable and satellite broadcasters can charge users to see a single program. In other words, if a user wants to see a specific movie, he or she can order the movie on a “pay-per-view” basis.
Such present day conventional televisions use, for example, NTSC or PAL system signals, and provide fairly good color pictures if receiving conditions are good. Such pictures, however, do not come close to having the sharpness, realism and visual impact as might be found, for example, in a motion picture film or a magazine-quality picture. To provide dramatically better television picture quality, experimental studies have been performed and components have been developed in an attempt to provide digital television pictures that approach the quality of a 35-millimeter color film. Such high-resolution television had been deemed especially advantageous for use, for example, in wide-screen theater and home television projection, and for theatrical motion picture production and projection using magnetic tape instead of film.
Several High-definition Digital Television, i.e., “HDTV” systems have already been proposed, the parameters of which are generally disclosed in a number of articles. In such systems, the lines per frame range from 1023 to 2125, the aspect ratios (picture width to picture height) range from 4:3 to 16:9 and luminance bandwidths range from 20 to 50 MHz. Recommendations have been made that an HDTV signal should be capable of standards conversions that would provide service to NTSC, PAL and SECAM domestic services.
Other techniques labeled as either high-definition or high-resolution television systems have modified the transmission of the conventional television signal to, for example, provide increased horizontal line resolution or better luminance resolution with less objectionable sub-carrier pattern.
Yet still another technique for improving the horizontal and vertical definition and reducing low frequency flicker in a conventional picture involves using digital signal processing technologies. Offset sampling is used to improve horizontal definition, and a double-rate stored image readout at the receiver selects the appropriate signal portions to subjectively increase the vertical definition and reduce low frequency (25 Hz) flicker.
Because of these efforts, high-definition digital television signals may eventually be delivered as the standard throughout the United States.
Like a standard television signal, HDTV may be broadcast over radio frequency (“RF”) airwaves, cable or satellite. However, to view an HDTV broadcast, users must buy an HDTV display and HDTV tuner. HDTV's are prohibitively expensive for many users when compared to standard television sets.
Simultaneously with the developments in high definition television, there has been an explosion in use and delivery of information, images, etc. through the Internet. As Internet broadband applications have grown, there has been a convergence between the Internet and conventional television. Thus, it is foreseen that eventually conventional television programming and permutations thereof, will be delivered to consumers through the Internet directly via broadband connectivity onto their computer monitor.
In addition, techniques are being developed to increase user control over the display of media content. One system currently available under the brand name “Tivo™ receives a standard television signal, simultaneously stores and displays the signal, and accepts user inputs such that the broadcast signal may be paused, rewound, or replayed based on user inputs. The system converts a standard television signal into Moving Pictures Experts Group (“MPEG”) format and parses the MPEG stream into video and audio components. The audio and video components are stored and then reassembled and decoded for delivery to a television receiver for display. The system accepts inputs from a user which controls when the stored, disassembled MPEG stream is reassembled, decoded and displayed. Such a system is described in U.S. Pat. No. 6,233,389, which is hereby incorporated in its entirety by reference. However, this technique is not applicable to a digital media environment.
In addition, current content distribution does not provide adequate control to send specific content to specific users and encrypt the content at the user level to avoid unauthorized distribution. These and other problems are avoided and numerous advantages are provided by the system and method described herein.